Keenan is an Irish surname from Ó Cianáin, a diminutive of Cian, and means "little ancient one" or "descendant of Cianán". As a first name it took off in the United States in the 1980s and 1990s, helped by comedian and director Keenen Ivory Wayans. Keenan peaked at number 532 in 2000, slid slowly for two decades, left the top 1000 in 2021 and ranks number 1307 in 2025.